1. Technical Field
The present invention relates to an optical scanner, an image display device, and a head mounted display.
2. Related Art
For example, Patent Document 1 (JP-A-2013-109359) discloses an optical scanner including a mirror part having a reflection surface, a torsion bar that swingably supports the mirror part, a support part that supports the torsion bar. Further, the optical scanner of Patent Document 1 has an impact relaxation part provided in an air gap between the mirror part and the support part, and the impact relaxation part prevents breakage of the mirror part due to collision with the support part. Furthermore, these respective parts are integrally formed by patterning of a silicon substrate using an etching technique.
However, in the optical scanner of Patent Document 1, spaces around the mirror part vary. That is, the space between the mirror part and the impact relaxation part is small compared to the space between the mirror part and the support part, and the shape of the impact relaxation part is very minute compared to the other parts. Accordingly, if the silicon substrate is patterned by etching, the amounts of processing vary in the respective parts of the silicon substrate due to differences in etching opening size, and manufacturing of the optical scanner is difficult.
Specifically, in order to form the impact relaxation part with higher accuracy, the etching time is longer. Then, the mirror part and the torsion bar are excessively etched, and the mirror part becomes smaller and the torsion bar becomes thinner. On the other hand, in order to form the mirror part and the torsion bar with higher accuracy, the etching time is shorter. Then, the etching may be ended before the impact relaxation part is formed.